Staff at the Butte County Mosquito and Vector Control District wouldn't be surprised if you were. They got several calls from area residents about "nuisance" mosquitoes.

The culprit is a type of mosquito known as Anopheles freeborni, according to a news release the district sent out this morning.

Cold weather kills most adult mosquitoes every year, according to the district. But many Anopheles freeborni females manage to survive the winter.

After laying their eggs, they look for a place to hibernate, often in garages, outbuildings or even thick grass.

When the weather warms up, they emerge from hibernation and are ravenous.

Those are the mosquitoes that may have been buzzing around and landing on you over the warm weekend.

The district's news release characterized these mosquitoes as mainly a nuisance. They are unlikely to carry West Nile virus, the release said.

They can carry malaria, however. In fact, their common name is western malaria mosquito.

In the late 1800s and early 1900s, these mosquitoes were involved in malaria epidemics in Northern California. Fortunately, malaria is rare these days, and transmission of the disease by these mosquitoes is not considered much of a risk.

The district can't stop the western malaria mosquito right now, the release said. Spraying isn't feasible because of weather conditions.

What people can do is avoid being outside in the late afternoon or at dusk, wear long-sleeved shirts if they are out, and use effective repellent.

It's also important to get rid of any standing water around the yard. That won't stop the hibernating mosquitoes, but it will remove places they could lay their eggs once there's an extended warm period.